Sheet Product Wrapping Apparatus

ABSTRACT

The apparatus includes a clamp lever  3  by which sheet products  1  are clamped near one edges thereof after being stacked. The clamp lever  3  is rotated at an angle of 180° so that the sheet products  1  are swung and turned over by the clamp lever  3 . The apparatus further includes a horizontal member  13  by which the sheet products  1  are received and supported, a press bar  14  being pressed against the sheet products  1  and then moved along the sheet products  1 . The sheet products  1  are therefore pushed and smoothed out by the press bar  14 . The sheet products  1  are wrapped with a wrapper  17  after being smoothed out.

FIELD OF THE INVENTION

The invention relates to a sheet product wrapping apparatus in which sheet products are wrapped with a wrapper after being stacked.

BACKGROUND

Each of Japanese Laid-Open Patent Publication No. S62-244,864 and Japanese Patent Publication No. H05-43,479 discloses a machine for successively making plastic bags. In the machine, a plastic film is fed longitudinally thereof and intermittently and heat cut widthwise thereof by a heat cutter whenever being fed intermittently, to successively make flexible plastic bags. The plastic bags are discharged successively after making.

Japanese Patent Publication No. H07-67,927 discloses an apparatus in which plastic bags are stacked with each other after being discharged. The plastic bags are then wrapped with a wrapper. The wrapper comprises a plastic film. The plastic bags are fed toward and across the plastic film to be surrounded by the plastic film. The plastic film is then heat cut by a heat cutter so that the plastic bags are wrapped with the plastic film.

In this case, some of the plastic bags may be slack or folded due to static electricity or air entrapment when the plastic bags are stacked with each other after being discharged. And sometimes, the plastic bags are wrapped as they are being slack or folded. It is strongly desired to overcome this problem.

Sheet products other than the plastic bags can be stacked with each other and then wrapped with the wrapper in the apparatus. However, some of the sheet products may be slack or folded in the same way when the sheet products are stacked with each other.

It is therefore an object of the invention to provide a sheet product wrapping apparatus in which sheet products are wrapped without being slack or folded after being stacked.

SUMMARY OF THE INVENTION

According to the invention, the apparatus includes a clamp lever by which sheet products are clamped near one edges thereof after being stacked. The clamp lever is rotated at an angle of 180° about a horizontal shaft extending parallel to the one edges so that the sheet products are swung and turned over by the clamp lever above the horizontal shaft. The apparatus further includes a horizontal member by which the sheet products are received and supported after being swung and turned over. A press bar extends parallel to the horizontal shaft. The press bar is pressed against the sheet products and then moved along the sheet products away from the clamp lever on the horizontal member. The sheet products are therefore pushed and smoothed out by the press bar. The sheet products are wrapped with a wrapper after being smoothed out.

In a preferred embodiment, a vertical member is disposed above the horizontal member. The sheet products are engaged with the vertical member at the other edges thereof after being swung and turned over. The press bar is moved along the sheet products to pass between the vertical member and the horizontal member so that the sheet products are guided by the vertical member to be folded by the press bar. The sheet products are wrapped with the wrapper after being folded.

The sheet products have a length, the press bar being moved to the other ends of the sheet products so that the sheet products are smoothed out throughout the length. The sheet products are then wrapped with the wrapper.

The clamp lever is spaced from a discharge position from which the sheet products are discharged. A stopper and a receiver are interposed between the clamp lever and the discharge position. The sheet products are discharged successively and engaged with the stopper at one edges thereof to be stacked on the receiver. The sheet products are then clamped by the clamp lever. The clamp lever is rotated to opposite side of the discharge position. The sheet products are swung to and turned over on the opposite side of the discharge position.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view (A) of a preferred embodiment of the invention, an explanatory view (B) of the clamp lever and the sheet products of (A) when the clamp lever is rotated and the sheet products are turned over and a plan view (C) of the clamp lever, the stopper and the receiver of (A).

FIG. 2 is a side view (A) of the clamp lever of FIG. 1 after being rotated and a side view (B) of the step next to (A).

FIG. 3 is a side view (A) of the step next to FIG. 2 and a side view (B) of the step next to (A).

FIG. 4 is a side view (A) of the step next to FIG. 3 and a side view (B) of another embodiment.

BEST MODE TO CARRY OUT THE INVENTION

Embodiments of the invention are as follows.

Turning now to the drawings, FIG. 1 illustrates a sheet product wrapping apparatus according to the invention. The apparatus is a plastic bag wrapping apparatus incorporated into a machine successively making plastic bags 1. The machine has the same structure as that of Japanese Laid-Open Patent Publication No. S62-244,864 or Japanese Patent Publication No. H05-43,479 and includes a heat cutter. In the machine, a plastic film is fed longitudinally thereof and intermittently and heat cut widthwise thereof by the heat cutter whenever being fed intermittently, to successively make the plastic bags 1. The plastic bags 1 are discharged successively after being made. For example, the plastic bags 1 are discharged from stacker belts 2. In addition, the plastic bags 1 are stacked with each other and then wrapped by the apparatus. It should therefore be understood that sheet products are wrapped by the apparatus. The sheet products comprise the plastic bags 1.

The apparatus includes a clamp lever 3 by which the plastic bags 1 are clamped near one edges thereof after being stacked. The clamp lever 3 includes clamp teeth 4 to clamp the plastic bags 1, the clamp lever 3 being supported by a horizontal shaft 5 for rotation about the horizontal shaft 5. The horizontal shaft 5 extends parallel to the one edges of the plastic bags 1. The clamp lever 3 extend vertically to have upper and lower ends, the clamp teeth 4 being positioned at the upper end while the horizontal shaft 5 is positioned at the lower end (FIG. 1A). The clamp lever 3 is rotated at an angle of 180° about the horizontal shaft 5 extending parallel to the one edges so that the plastic bags 1 are swung and turned over by the clamp lever 3 above the horizontal shaft 5. The clamp lever 3 is rotated at high speed in a direction X so that the plastic bags 1 are swung at high speed. The clamp lever 3 is rotated at the angle of 180° to merely take a time of less than a second. As a result, the plastic bags 1 are subject to inertia force F1 and centrifugal force F2 when being swung so that resultant force F3 acts longitudinally of the plastic bags 1 (FIG. 1B).

The clamp lever 3 is spaced from a discharge position from which the plastic bags 1 are discharged. A stopper 6 and a receiver 7 are interposed between the clamp lever 3 and the discharge position. The plastic bags 1 are discharged successively and engaged with the stopper 6 at one edges thereof to be expelled successively and struck against the stopper 6. The discharge position is formed by the stacker belt 2. The stopper 6 extends vertically while the receiver 7 extends horizontally, between the clamp lever 3 and the discharge position. The plastic bags 1 therefore fall along the stopper 6 after being struck, to be stacked on the receiver 7. The plastic bags 1 are then clamped by the clamp lever 3, the clamp lever 3 being rotated to the opposite side of the discharge position so that the plastic bags 1 are swung to and turned over on the opposite side of the discharge position.

In the embodiment, the stopper 6 comprises a plate including slots 8 formed therein. The receiver 7 also comprises a plate including slots 9 formed therein. The clamp lever 3 is provided with a holder 10 and fixed to the horizontal shaft 5. The holder 10 extends horizontally and parallel to the horizontal shaft 5 to be cantilevered. In addition, two pairs of teeth 4 are held on the holder 10. The apparatus includes a clamp lever drive 11 comprising an actuator such as a motor, which is connected to the horizontal shaft 5. The horizontal shaft 5 is rotated by the clamp lever drive 11 when the plastic bags 1 are clamped after being stacked, so that the clamp lever 3 is rotated clockwise about the horizontal shaft 5 to advance the clamp teeth 4 toward the plastic bags 1 through the slots 8. The holder 10 is provided with a clamp teeth drive by which the clamp teeth 4 are closed after advancing so that the plastic bags 1 are clamped by the clamp teeth 4 at positions of slots 9 (FIG. 1C).

The apparatus further includes a stopper drive 12 comprising an actuator such as a cylinder, which is connected to the stopper 6 so that the stopper 6 is pulled down and lowered by the stopper drive 12 after the plastic bags 1 are clamped. The horizontal shaft 5 is then rotated by the clamp lever drive 11 so that the clamp lever 3 is rotated counterclockwise about the horizontal shaft 5. It should therefore be understood that the plastic bags 1 are swung and turned over by the clamp lever 3 above the horizontal shaft 5. The clamp lever 3 is rotated to the opposite side of the discharge position so that the plastic bags 1 are swung to and turned over on the opposite side of the discharge position. The stopper 6 is then pushed up and raised by the stopper drive 12.

The apparatus further includes a horizontal member 13 by which the plastic bags 1 are received and supported after being swung and turned over, as shown in FIG. 2. The horizontal member 13 comprises a plate extending horizontally. A press bar 14 extends parallel to the horizontal shaft 5. The press bar 14 is pressed against the plastic bags 1 and then moved along the plastic bags 1 away from the clamp lever 3 on the horizontal member 13. For example, the apparatus includes a bar drive 15 comprising an actuator such as a cylinder, the press bar 14 being connected to and supported by the bar drive 15. The press bar 14 is actuated by the bar drive 15 to be pressed against the plastic bags 1 and then moved along the plastic bags 1 after the plastic bags 1 are swung and turned over. The plastic bags 1 are therefore pushed and smoothed out by the press bar 14 (FIG. 2A).

In addition, a vertical member 16 is disposed above the horizontal member 13. The vertical member 16 comprises a plate extending vertically. The plastic bags 1 are engaged with the vertical member 16 at the other edges thereof after being swung and turned over. The press bar 14 is moved along the plastic bags 1 to pass between the vertical member 16 and the horizontal member 13 so that the plastic bags 1 are guided by the vertical member 16 to be folded by the press bar 14. The plastic bags 1 are wrapped with a wrapper after being smoothed out and folded.

In the embodiment, the wrapper comprises a plastic film 17. The plastic film 17 is supplied from a supply roll 18 to extend vertically and pass through guide rollers 19 and 20 and feed rollers 21. The plastic film 17 is then directed to and taken up about a take up roll 22. The clamp teeth 4 are opened by the clamp teeth drive so that the plastic bags 1 are released from the clamp teeth 4 and pushed and moved by the press bar 14 after being folded (FIG. 2B). The plastic bags 1 are therefore fed toward and across the plastic film 17 between the guide rollers 19 and 20 to be covered with the plastic film 17, as shown in FIG. 3. In addition, fingers 23 are disposed on the opposite side of the plastic bags 1 fed across the plastic film 17. The fingers 23 are connected to and supported by a finger drive 24 comprising an actuator such as a cylinder. The fingers 23 are closed by the finger drive 24 after the plastic bags 1 are covered with the plastic film 17 so that the plastic film 17 and the plastic bags 1 are gripped by the fingers 23 (FIG. 3A).

Subsequently, the press bar 14 is actuated by the press bar drive 15 to be moved longitudinally thereof and pulled out from the plastic bags 1. The fingers 23 is then moved by the finger drive 24 so that the plastic film 17 and the plastic bags 1 are pulled and moved by the fingers 23. The plastic film 17 is guided by the guide rollers 19 and 20 so that the plastic bags 1 are surrounded by the plastic film 17 (FIG. 3B). In addition, the press bar 14 is moved by the press bar drive 15 to be returned to the original position. The plastic film 17 is sandwiched and heated by a heat cutter 25 after the plastic bags 1 are surrounded by the plastic film 17, to be heat cut widthwise thereof by the heat cutter 25. Furthermore, the plastic film 17 is sandwiched between and heated and side sealed by side seal bars 26 so that the plastic bags 1 are wrapped with the plastic film 17.

The plastic film 17 and the plastic bags 1 are then moved by the fingers 23 to be put on a conveyor 27, as shown in FIG. 4, and fed by the conveyor (FIG. 4A). The plastic film 17 is fed by the feed rollers 21 and taken up about the take up roll 22. The plastic film 17 may be taken up by a small amount.

The clamp lever 3 is rotated by the clamp lever drive 11 to advance the clamp teeth 4 toward the plastic bags 1 again, after the plastic bags 1 are stacked on the receiver 7. The clamp teeth 4 are then closed by the clamp teeth drive so that the plastic bags 1 are clamped by the clamp teeth 4. The stopper 6 is lowered by the stopper drive 12, the clamp lever 3 being rotated by the clamp lever drive 11 so that the plastic bags 1 are swung and turned over. The same steps are then performed repeatedly.

It should therefore be understood that in the apparatus, the plastic bags 1 are discharged successively and engaged with and struck against the stopper 6 at the one edges thereof. The plastic bags 1 are then fall along the stopper 6 to be stacked on the receiver 7. The plastic bags 1 are therefore stacked to have the one edges aligned with each other.

Subsequently, the plastic bags 1 are clamped near the one edges thereof by the clamp lever 3. The plastic bags 1 are then swung and turned over by the clamp lever 3. The plastic bags 1 are then pushed and smoothed out by the press bar 14 and wrapped with the plastic film 1.

Accordingly, the apparatus has no problem even if some of the plastic bags 1 are slack or folded due to static electricity or air entrapment when the plastic bags 1 are stacked with each other after being discharged. The plastic bags 1 are subject to the inertia force F1 and the centrifugal force F2 when being swung so that the resultant force F3 acts longitudinally of the plastic bags 1. The plastic bags 1 are therefore pulled and smoothed out by the resultant force F3. In addition, the plastic bags 1 are pushed and smoothed out by the press bar 14 after being turned over. The plastic bags 1 are then wrapped as they are. The plastic bags 1 cannot be wrapped in the state of being slack or folded.

The plastic bags 1 are not necessarily folded by the press bar 14 and wrapped as they are. The clamp teeth 4 may be kept being closed while the press bar 14 is moved along the plastic bags 1. The plastic bags 1 have a length, the press bar 14 being moved to the other edges of the plastic bags 1 so that the plastic bags 1 are smoothed out throughout the length. In this case, the plastic bags 1 are not folded by the press bar 14. The plastic film 17 and the plastic bags 1 are then gripped by the fingers 23. The clamp teeth 4 are opened by the clamp teeth drive so that the plastic bags 1 are released from the clamp teeth 4. The plastic film 17 and the plastic bags 1 are then pulled and moved by the fingers 23 so that the plastic bags 1 are surrounded by the plastic film 17. In addition, the plastic film 17 is heat cut and side sealed by the heat cutter 25 and side seal bars 26 so that the plastic bags 1 are wrapped with the plastic film 17.

As to the clamp teeth 4 and the horizontal shaft 5 positioned at the upper and lower ends of the clamp lever 3, the clamp teeth 4 may be positioned at the lower end of the claim lever 3 while the horizontal shaft 5 is positioned at the upper end of the clamp lever 3 (FIG. 4B). The clamp lever 3 is rotated at an angle of 180° about the horizontal shaft 5 so that the plastic bags 1 are swung and turned over by the clamp lever 3 about the horizontal shaft 5.

Sheet products other than the plastic bags 1 can be wrapped in the apparatus after being discharged successively and stacked with each other. The sheet products may be wrapped with a wrapper other than the plastic film 17. 

What is claimed is:
 1. A sheet product wrapping apparatus comprising: a clamp lever by which sheet products are clamped near one edges thereof after being stacked: a lever drive by which the clamp lever is rotated at an angle of 180° about a horizontal shaft extending parallel to the one edges so that the sheet products are swung and turned over by the clamp lever above the horizontal shaft: a horizontal member by which the sheet products are received and supported after being swung and turned over; a press bar extending parallel to the horizontal shaft; and a bar drive by which the press bar is pressed against the sheet products and then moved along the sheet products away from the clamp lever on the horizontal member, the sheet products being pushed and smoothed out by the press bar, the sheet products being wrapped with a wrapper after being smoothed out.
 2. The apparatus as set forth in claim 1 further comprising: a vertical member disposed above the horizontal member, the sheet products being engaged with the vertical member at the other edges thereof after being swung and turned over, the press bar being moved along the sheet products to pass between the vertical member and the horizontal member so that the sheet products are guided by the vertical member to be folded by the press bar, the sheet products being wrapped with the wrapper after being folded.
 3. The apparatus as set forth in claim 1 wherein the sheet products have a length, the press bar being moved to the other edges of the sheet products so that the sheet products are smoothed out throughout the length, the sheet products being then wrapped with the wrapper.
 4. The apparatus as set forth in claim 1 wherein the clamp lever is spaced from a discharge position from which the sheet products are discharged, a stopper and a receiver being interposed between the clamp lever and the discharge position, the sheet products being discharged successively and engaged with the stopper at one edges thereof to be stuck on the receiver, the sheet products being then clamped by the clamp lever, the clamp lever being rotated to opposite side of the discharge position, the sheet products being swung to and turned over on the opposite side of the discharge position. 